Hydraulic crane with telescopic mast



Jan. 9, 1951 W.'HARBAUGH HYDRAULIC'CRANE WITH TELESCOPIC MAST 2 Sheets-Sheet 1 Filed March 31, 1947 HQ q 0 5 l figq:

INVEN TOR. hlqz TE]? HAHBA UGH, Y BY ATTORNEY 1951 w. HARBAUGH 2,537,755

HYDRAULIC CRANE WITH TELESCOPIC MAST Filed March 31, 1947 2 Sheets-Sheet 2 lllllllllllgggllll gay Ma i M Patented Jan. 9, 1951 2,537,755 HYDRAULIC. CRANE WITH TELESCOPE? MAST Walter Harbaugh, Indianapolis, Ind. Application March 31, 1947; Serial-No. 738,475

12 Claims.

The present invention. relates. to a hydraulic crane, and is particularly concerned with an improvement upon the invention disclosed and claimedin myco-pending application Serial No.

end ,oithe' boom'beingtethered toa mast, wherev by elongation of the boom results in elevation of the outer end ofv the boom, it will be obvious that theefliciency of the. elevating mechanism will depend to some extent upon the, difference in elevatio'n between. the outer end. of the boom and the; point on the mast to which it is tethered. The higher the-latter .point is located, the. more efficient will' bethe' operation of the crane as a whole; However,. the IIlOllIltiIlg: of a tall. mast upona truck or other automotive vehicle is impractical, because of the necessity for clearing road obstructions, doorways," and the like. There.- fore, iniorder to attain .the operating advantages of; a tall mast while' providing for ample cleare ance,..I have conceived the provision of a telescopicimast, together with means, automatically operable'during. elevation of the boom, for progressively' increasing the efiective height of the mast; and the" primarvpbj'ect of' the present in-.- vention is to provide such means.

In* relatively light installations, constructed in accordance with the present invention, the sole power means. for. the crane may be that means which actsupon the telescopic boom.elements to increase the effective length of the boom; and the mast .will be elongated as the boom is elongated; Injheavierinstallations,however. it may. be desirable to provide power means operating, upon the mast, instead of, or as well as power means operating uponthe boom element; and a fur.-. ther object. of my. invention. is the provision of fluidpressure means, suitably controlled byvalve means,- for..acting. upon the. telescopic .boom and upon .the telescopic..mast,.,-sim-ultaneously to effect a desired operation of the crane-as a whole.

Further objects f-thewiI1V8llti0n-Wl1I appear as..the .description. proceeds;

To. theaccomplishment of the above and related: objects;.-=my invention may 'be embodied in the form illustrated inthe accompanying drawings attention being called to thefact, however, thatstheidrawings are illustrative-only, and that change may b'eimade inthe specific construction illustrated! and describedgso long as the scope chine-appended 'laims isnot violated- Fig. 11s a sidelelevation of a truckupon. which my improved crane is erected;

Fig. 2 is a fragmental view, upon an enlarged scale,..showing.. the. boom. in transverse section, substantially onthe line 2.-2.of Fig. 1, and. showing themast in rear elevation;

Fig. 3 is a horizontal section taken. substantial.- ly on the line 3-3-of Fig.2;

Fig. 4 is astill furtherenlarged,longitudinal sectionalviewthrough a valve mechanism. incorporated in the illustrated embodiment or. the invention;

Fig. 5 is a horizontal section. takensubstantial- 1y on the line 55 of Fig. 4; and.

Fig. 6 is a. plan view,.upon. a reducedscalaof my crane and the vehicle upon whichit i'smounted..fl

Referring more particularly to the drawings,.it will be seen that I have illustrated. a truck. [0 having a .frame 5 l upon which. is mounted. a rectangular. bed. I! and. a. cab. l-.3. The truckis provided with. the usual. prime. mover. which, through a transmission. l4, drives the power Wheels. of the vehicle; and said transmissi'onincludes a power take-01f operatively connected to drive a-pump l5..

Mo unted up onthe. bed! 2, and preferably at one corner thereof adjacent. the cab I3, is a mastindicated generally by the. reference numeral "5, and comprising. an upstanding, hollow. cylindrical element !.1,,having.a bore 18, openat itsupper end for the telescopic receptionrof. a plunger I9. The elements H and l9constitute a fiuidmotor, and the plunger 19 will preferably be provided-,='at its inner end, with a sealing cup. 20 of known construction. Upon its upper end, the plunger is will preferably carry a. platform 21, mounting a winch, indicated generally. by the reference. numeral 22, said winch beingv of any desired construction, and being .either manually or power operated.

A ring or sleeve. 23 is swivelly mounted upon the element I! for oscillatory movement about the axis of said element,.but is held against axial movement relative thereto bysuitable sto rings 24.and 2.5. Said sleeve carries a radially project-.- ing bralcketszs upon which ispivotally mounted the. inner end of a. boom, indicated. generally bythe reference numeral 21.

I The boom. 27 comprises a cylinder. member.28

and. a piston member 29,. the inner endofsaid member 28 being closed. and the outerend-theree of.'being open for the. telescopic reception. of theplunger piston 29;. andpreferably, the, inner end, of 'said piston will carry a sealing cup 30. The

inner closed end of the member 28 is received between the opposite furcations of the bracket 26 and is pivotally secured thereto by means of a pivot pin 3|, so that the boom is oscillable, relative to the bracket 23, about a substantially horizontal axis.

Two tension members 32 are connected to the outer end of the boom piston member 29 at 33, and to the plunger l9, adjacent the upper end thereof at 34. Thus, the outer end of the boom piston member 29 is so tethered to the plunger 19 as to maintain a fixed distance between the points 33 and 34, at all times. The proportions of the parts are such that, when the boom 2'! is in a horizontal position, its effective length is substantially equal to the distance from the mast 13 to the diagonally opposite corner of the truck bed 12. Consequently, goods supported upon the crane may be deposited relatively accurately at substantially any point on the bed l2. A compression beam 35 is pivoted at 36 to a bracket fixed on the boom cylinder member 28, and at 31 to a bracket fixed to the plunger l9 near the upper end thereof. This connection is such as to maintain, at all times, a fixed distance between a point on the boom cylinder member and a point on the plunger. Preferably, a sheave 38 will be mounted on the outer end of the boom piston member 29, and a cable 39, wrapped upon the drum of the winch 22, passes over said sheave and carries, at its outer end, a cargo hook-4U.

It will be apparent from the above description that the geometry of the connected elements is such that, when the boom piston member 23 is driven outwardly, the tension members 32 will swing upwardly, maintaining a fixed distance between the points 33 and 34, thereby causing the boom to swing upwardly about its pivotal mounting 3|. Such movement of the boom will act, through the compression member 35, to lift the plunger i9, thereby progressively moving the pivot point 34 for the tension members 32, higher and higher to maintain an eifective work angle between said tension members 32 and the boom 28.

It will be clear from the drawings that the mast elements may be so proportioned that the winch 22 will not project above the cab l3 when the boom is in horizontal, inactive position, so that the crane will not present a problem in connection with road and doorway clearances; and yet the plunger may be projected well above the cab top, during operation, as the boom 2? is lifted.

While the parts may be pneumatically controlled, I prefer to control them hydraulically, and have so illustrated my invention. A liquid reservoir 4i, suitably supported on the vehicle, is connected by piping 42 with the intake of the pump 15; and a pipe 43 leads from the exhaust port of said pump upwardly to penetrate the bed i2 of the vehicle. A flexible conduit 4 connects the upper end of the pipe 43 with a control valve indicated generally by the reference numral 45. In the illustrated embodiment of my invention, the valve 45 comprises a casing 46 having a valve chamber 41 and provided with an inlet port 48, to which the conduit 34 is connected; an exhaust port 39,, which may preferably be diametrically opposite the port as, but

axially displaced therefrom; an outlet port 53, displaced 90 degrees from the ports 48 and A: and axially offset, in the opposite direction, from the port 48; and an outlet port 5|, diametrically opposite the port 50, and preferably aligned therewith. Reciprocably mounted in the chamber 41 is a valve body 52 formed with two axially spaced lands 53 and 5d, and having a stem 55 axially projecting from the chamber. A spring 52' resiliently retains the valve body in its illustrated position, in which the land 53 seals the ports 50 and SI against fluid flow, and in which the ports 48 and as are open for direct flow therethrough. An actuating lever 56 is pivotally mounted at 5] outside the casing, and may be rocked to depress the valve 52 against the influence of the spring 52. Depression of the valve body moves the land 5t across the port 49 to reduce the effective area of said port, and ultimately to close the same. It will be readily perceived that the valve is so proportioned and designed that the ports 53 and 53 are progressively opened as the port 48 is progressively closed, and vice versa. Thus, a very delicate control of flow may be maintained, any desired proportion of the flow being directed through the ports 58 and 5i, while the remaining portion thereof continues to bleed through .the port 49.

Connected to the port 39 is a pipe 58 leading to a three-way fitting 59 from another branch of which leads a flexible conduit 36 connected to piping 5! projecting through the bed l2 and communicating with the storage reservoir 4|. Thus, so long as the port 49 is open, and the pump i5 is being driven, fluid will be circulated from the reservoir through the pump, through the ports 48 and 59, through the fitting 59 and the conduits 83 and 5!, back to the reservoir.

A flexible conduit 62 leads from the port 50 to an inlet port 63 formed in the lower portion of the upstanding element I1 and communicating with the bore thereof. A pipe 64 leads from the port 5|, through a check valve 65, to the interior of the boom cylinder member 28, near the inner closed end thereof. Thus, as the valve 52 is depressed, fluid will be directed to the chamber within the element ll and to the chamber within the element 28 to elevate the mast plunger I3 and to project the boom piston. 28. The check valve 55 operates not only to prevent reverse flowof fluid from the interior of the member 28 toward the valve 45, but also to prevent the flow of fluid, at a pressure less than a predetermined minimum, to the cylinder member 28.

An exhaust port 66 provided in the base of the element H, is connected by a flexible conduit 61 with a port 68 of a valve mechanism 69, similar in construction to the valve mechanism 45. Similarly, a pipe H provides communication between the interior of the boom cylinder member 28 and a port 19 of the valve mechanism 69, diametrically aligned with the port 68. The valve stem 12 of the mechanism 69 projects from the valve casing and may be depressed by oscillation of a lever 13 pivoted at '14 on said casing. With the valve in its normal position, the ports 68 and 10 are closed; but when said valve is depressed, communication between said ports and a third port 15 is established, said port 15 being connected, by a pipe 16, with the third branch of the fitting 59.

' I claim as my invention:

1. A crane comprising a mast including a substantially vertically arranged hollow base and a plunger reciprocably received therein, a boom hingedly associated with said base and comprising a hollow member and a second member telescopically received in said hollow member, means for maintaining a fixed distance between a point on said hollow member and a point on said plunger, means for maintaining a. fixed distance telescopic elongation of between: point .on. said. second members. and a point onsaid. plunger, andrneans .for. varyingxthe distance between saidpoint. on said hollowmeme ber. and said point. on: said. second members.

2. The crane of claim- 1 in which;saidipiunger andthe hollowin said. base. are cylindrical, the axis ofv the hin edconnection between said. base. and; saidboom. is substantially. horizontal, .and said. axis ,is'connectedto said base for peripheral movement thereabout.

3. A crane comprising a mast unit of variable length including ,a substantially vertically arranged hollow base and a plunger reciprocably received therein,.a boom unit of. variable length hingedly associated with said base and comprising a: hollow member and a second member telescopically received insaid hollow: member, means forlmaintainmga fixeddistance between a point on .said hollow member and: a point on said plunger, means for maintaining a fixed distance between a point on said second member and a point on said plunger, and means for enforcing one of said units of variable length.

4. A fluid operated crane comprising a mast including a substantially vertically arranged hollow member and a plunger reciprocably received therein, a boom hingedly associated with said hollow member and comprising a second hollow member and a second plunger telescopically received in said second hollow member, the inner end of one of said plungers being provided with means establishing a sliding fluid seal with the walls of its associated hollow member, a source of fluid under pressure, means for controlling the flow of fluid from said source to the interior of said associated hollow member, means for controlling the flow of fluid from the interior of said associated hollow member, means for maintaining a fixed distance between a point on said second hollow member and a point on said first-named plunger, and means for maintaining a fixed distance between a point on said second plunger and a point on said first named plunger.

5. A fluid operated crane comprising a mast including a substantially vertically arranged hollow base and a plunger reciprocably received therein, a boom hingedly associated with said base and comprising a hollow member and a second member telescopically received in said hollow member, the inner ends of said plunger and of said second member being provided with means establishing fluid seals with the walls of said base and of said hollow member, respectively, a source of fluid under pressure, valve means for concurrently controlling the flow of fluid from said source to the interiors of said base and said hollow member, valve means for concurrently controlling the flow of fluid from the interiors of sad base and said hollow member, means for maintairing a fixed distance b'=ween a point on said hollow member and point on said plunger, and means for a fixed distance between a point on said second member and a point on said plunger.

6. A crane comprising a mast and a boom, said mast comprising an upstanding hollow cylindrical base and a cylindrical plunger reciprocably received in said base, a sleeve swivelly supported on said base, means retaining said sleeve against substantial axial movement relative'to said base, a bracket fixed to said sleeve, said boom comprisin a hollow elongated member, means at one end of said member connecting said member to said bracket to swing with respect thereto about a substantially horizontal axis, and a secondmember. .havingone. end telescopically receivedv inrthe open. freewend. of .said .hollow members means member.

7; -A hydraulic crane comprising a. mast. anda boom, said mastcomprising acylinder member and a. piston member telescopically associated therewith,. a sleeve swivelly-supportedon one of I saidmast members and held against. axial-move ment relativethereto, said boom comprising a cylinder member-and a piston member. tele-- scopically associated-therewith, means pivotal-1y connectin one of said boom members to said sleevefor movement relative thereto-- about a substantially horizontal axis, means tethering-the remote end of the other of saidboom membersagainst movement away-froma fixedpoint onthe other of said mast members, meansestabli'shing a fixed distance between a point on said one boom member and a point on said other mast member, a source of fluid under pressure, and meansfor controlling fluid flow from said source into one of said cylinder members, and out from said one cylinder member.

8. A hydraulic crane comprising a mast and a boom, said mast comprising a cylinder member and a piston member telescopically associated therewith, a sleeve swivelly supported on one of said mast members and held against axial movement relative thereto, said boom comprising a cylinder member and a piston member telescopically associated therewith, means pivotally connecting one of said boom members to said sleeve for movement relative thereto about a substantially horizontal axis, means tethering the remote end of the other of said boom members against movement away from a fixed point on the other of said mast members, means establishing a fixed distance between a point on said one boom member and a point on said other mast member, a source of fluid under pressure, and means for controlling fluid flow from said source into said cylinder members and out from said. cylinder members.

9. The device of claim 7 including a sheave carried at the remote end of said other boom member, a winch carried on the upper end of said other mast member, and a cable wound on said winch and passing over said sheave.

10. For use with an automotive vehicle having a bed, a cab, a prime mover, and a power take-off, a fluid operated crane comprising an, upstanding hollow cylindrical element mounted on said bed and projecting thereabove a distance not in excess of the height of said cab above said bed, a plunger reciprocably received in the open upper end of said hollow element, a sleeve swivelly mounted on said element for oscillation about the axis thereof, a boom comprising a cylinder member and a piston member telescopically received in said cylinder member, one end of one of said members being pivotally mounted on said sleeve for swinging movement relative thereto about a substantially horizontal axis, a tension member connecting the other of said boom members to said plunger, a compression member connecting said one boom member to said plunger, and fluid pressure means for controlling relative reciprocation of said boom members.

r 11. For use with an automotive vehicle havin a rectangular bed, a cab, a prime mover, and a power take-off, a fluid operated crane comprising. an upstanding hollow cylindrical element mounted near one corner of said bed adjacent said cab and projecting above said bed a distance not in excess of the height of said cab above said bed, a plunger reciprocably received in the open upper end of said hollow element, a sleeve swivelly mounted on said element for oscillation about the axis thereof, a boom comprisin a cylinder member and a piston member telescopically received in said cylinder member, one end of one of said members being pivotally mounted on said sleeve for swinging movement relative thereto about a substantially horizontal axis, a tension member, having an efiective length substantially equal to the horizontal distance from said upstanding element to the diagonally-opposite corner of said bed, connecting the other of said boom members to said plunger, a compression member connecting said one boom member to said plunger, and fluid pressure means for controlling relative reciprocation of said boom members.

8 12. The device of claim 10 in which said fluid pressure means comprises a pump, means connecting said power take-off to drive said pump, conduit means connecting said pump to supply fluid under pressure to said cylinder member, valve means controlling flow through said conduit means, and other valve means controlling fluid flow from said cylinder member.

WALTER HARBAUGH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 741,525 Mitchell Oct. 13, 1903 1,589,727 Travell June 22, 1926 2,290,384 Rowe July 21, 1942 2,446,586 Harbaugh Aug. 10, 1948 2,475,963 Howell July 12, 1949 

